Video decoding and transcoding method and system

A video decoding and transcoding system, which decodes, displays and transcodes a video stream with a sequence of frames and produces decoded frames having a first field and a second field each, the system comprising:

• a memory, which has a plurality of frame buffers to temporarily store the frames of the video stream on decoding and transcoding;
• a decoding unit, which is connected to the memory, in order to receive and decode the video stream to accordingly produce the decoded frames and write the decoded frames respectively to the frame buffers assigned of the memory, wherein the decoding unit checks whether said frame buffer is usable when a previous frame is completely decoded and subsequently decodes a current frame to accordingly produce the decoded frame, temporarily stores the decoded frame in the frame buffer and sets a frame flag corresponding to the frame buffer when the frame buffer is usable;
• a displaying unit, which is connected to the memory, in order to read and display the decoded frames temporarily stored in the frame buffers assigned of the memory, wherein the displaying unit checks whether the frame buffer temporarily stores the decoded frame when a previous field is completely displayed and subsequently reads and displays the decoded frame when the frame buffer temporarily stores the decoded frame;
• and
• a transcoding unit, which is connected to the memory in order to read data from the assigned frame buffer assigned and send the data to an encoding unit for performing an encoding operation and producing a corresponding bitstream, wherein the transcoding unit checks whether the frame buffer temporarily stores the decoded frame when the previous frame is completely decoded and subsequently reads and transcodes the decoded frame when the frame buffer temporarily stores the decoded frame.

A video decoding and transcoding system, which decodes, displays and transcodes a video stream with a sequence of frames and produces decoded frames having a first field and a second field each, the system comprising:

• a memory, which has a plurality of frame buffers to temporarily store the video stream on decoding and transcoding;
• a decoding unit, which is connected to the memory in order to receive and decode the video stream to accordingly produce a decoded frame and write the decoded frame to the frame buffer assigned of the memory;
• a displaying unit, which is connected to the memory in order to read and display the decoded frame temporarily stored in the frame buffer assigned of the memory;
• a transcoding unit, which is connected to the memory in order to read data from the frame buffer predetermined and send the data to an encoding unit for performing an encoding operation and producing a corresponding bitstream;
• and
• a controller, which is connected to the decoding unit, the displaying unit and the transcoding unit, in order to initialize and control an operation timing of the decoding, displaying and transcoding units and access the frame buffers, wherein the controller numbers the frame buffers to thereby control the operation timing of the decoding, displaying and transcoding units.